This invention relates generally to a document handling system for transporting sheets to and from a fusing station and more particularly concerns a document handling system for sequentially transporting sheets to and from the fuser having a selectable shunt or buffer path permitting selected sheets to bypass the fuser station.
The primary output product of a typical printing machine is a printed substrate, such as a sheet of paper bearing printed information in a specified format. Quite often, customer requirements necessitate that this output product be configured in various specialized arrangements or print sets ranging from stacks of collated loose printed sheets to tabulated and bound booklets. Even when using state of the art document producing and finishing apparatus, it may be necessary to insert sheets into the document which are produced by means other than the document producing apparatus, or produced at a separate time from the majority of the sheets contained in the print set. For example, it is not uncommon to place specially colored sheets, chapter dividers, photographs or other special insert sheets into a print set to produce a final document. For example, it is common to use preprinted sheets which were produced by four-color offset press techniques as special insert sheets in a document containing mostly text printed on ordinary white paper. In another example, booklets produced from signatures, often use special cover sheets or center sheets containing, for example, coupons. It is generally not desirable to pass these sheets through the fuser station because the ink on the special insert sheets tends to be smudged or damage by heat of the fuser roll, etc. In addition, these special insert sheets may be of a particular weight stock or may include protruding tabs which may cause jams when transported through the fuser station.
Accordingly, these special insert sheets must be inserted into the stream of sheets subsequent to processing in the printer processor section of the document producing apparatus. It is desirable to insert these sheets without disrupting the flow of the continuous stream of processed sheets. It is also desirable to insert these sheets in a manner which is transparent to the print processor on the finishing apparatus so that the operation of these apparatus need not be modified. The following disclosures relate to the area of inserting one or more insert sheets among a plurality of previously marked sheets:
U.S. Pat. No. 5,272,511, Patentees: Conrad et al., issued: Dec. 21, 1993.
U.S. Pat. No. 4,961,092, Patentee: Rabb et al., issued: Oct. 2, 1990.
U.S. Pat. No. 4,602,776, Patentee: York et al., issued: Jul. 29, 1986.
U.S. Pat. No. 4,561,772, Patentee: Smith, issued: Dec. 31, 1985.
U.S. Pat. No. 4,536,078, Patentee: Ziehm, issued: Aug. 20, 1985.
U.S. Pat. No. 4,248,525, Patentee: Sterret, issued: Feb. 3, 1981.
Xerox Disclosure Journal--Vol. 19, No. 4, pp. 333-336, Patentee: John R. Yonovich, Disclosed: July/August 1994.
U.S. Pat. No. 5,272,511 discloses a sheet inserter for inserting one or more special insert sheets into a continuous stream of sheets by overlaying the insert sheets with a corresponding sheet in the continuous stream of sheets. The insert sheet overlaying the corresponding sheet in the continuous stream of sheets is then conveyed with the corresponding sheet to a final destination where the sheets can be compiled into a stack.
U.S. Pat. No. 4,961,092 discloses a preprogrammed post-collation system for a copier which uses plural sorter bins and a recirculating document handler. Preprogrammable pause points in the copying operation allow for repeatedly inserting a variable number of job inserts or other special copy sheets into the bins being filled (by producing copies of these special documents or by manually inserting them into the bins), at any selected document copying point. The copying sequence must be manually restarted after the appropriate insertion operation is completed.
U.S. Pat. No. 4,602,776 discloses an insertion apparatus for use with a copier and/or a collator for providing on-line and off-line insertion of sheet material or collation, respectively. A supply tray is loaded with one or more types of insert material, each type being separated by a first type of coded sheet. A copying operation is interrupted when a second type of coded sheet, located in the stack to be copied and indicating a location where insert sheets are to be inserted, is detected. As the insert sheets are fed, a second sensor detects the first type of coded sheet (indicating the end of the group of insert sheets), which is then fed to an overflow tray. The normal copying operation is then resumed.
U.S. Pat. No. 4,536,078 discloses an automatic document handling system for recirculative document duplex copying to provide precollated simplex or duplex copies with proper image orientation on the output copy sheet for copies made on special orientation restricted copy sheets as well as non-orientation sensitive copy sheets. A switching system is provided for selecting between feeding of copy sheets from a main supply tray or a special copy sheet supply tray. A control system is provided for causing the document handling system to circulate the input copy sheets once before copying, to count the input copy sheets and to determine whether an odd or even number of input sheets are being provided to improve operating efficiency.
Smith U.S. Pat. No. 4,561,772 discloses several approaches for inserting orientation sensitive paper into a copier with a paper path loop and two paper trays disposed adjacent the loop. With the Smith copier, orientation sensitive paper can be loaded into one of the trays for feeding into the loop in accordance with the marking requirements of a copy job. In one example, a system operator informs the controller of the copier of the presence of orientation sensitive paper by activating a switch or button. Accordingly, the copy job is processed, in part, on the basis of the switch being activated.
U.S. Pat. No. 4,248,525 discloses an apparatus for producing sets of collated copies wherein some of the sheets in a document (regular sheets) can be reproduced in a collating mode by means of a copier having a recirculating document handler (RDH), while other sheets in the document (insert sheets) cannot be produced in a collating mode by the RDH. Each sheet which cannot be imaged using the RDH is first individually copied multiple times and fed to a separate storage bin. These sheets later will be inserted into the stream of collated regular sheets as they are copied and output from the copier. A controller is preprogrammed with the page numbers of the sheets to be inserted. The regular sized sheets are then placed (in order) in the RDH, and multiple collated copies are made and fed toward a finisher (stapler). Copies of the regular sized sheets in the document are thus output from the copier in order (collated), with the insert sheets missing. Since the controller keeps track of the number of sheets being copied, the controller is able to temporarily stop the RDH at the appropriate time and cause the appropriate insert sheet to be fed from its corresponding storage bin into the stream of regular sheets output from the copier. Thus, collated complete print sets of a particular document are generated.
The Xerox Disclosure Journal article discloses a dual function sheet feeder including first and second sheet feeding paths which share common initial document path portion, diverting at a gate to provide separate functions. The first sheet feeding path allows input documents to be transported for document imaging and onward to a document restacking tray. The second sheet feeding path allows transport of input documents into a print engine input path to be merged into the regular sheet feeding path for delivery to the finisher.
In various known printing systems, marking software is employed, in conjunction with one or more controllers, to implement a sheet scheduling technique. More particularly, in one known system each page of a job is programmed for printing and the corresponding marking related information is communicated to a print manager node. In turn, the print manager node generates a schedule indicating the sequence in which the sides of the job pages are to be printed. This is a straightforward process, provided each page is to be printed in simplex. If, however, selected ones of the pages are to be printed in duplex with a multipass approach, then the schedule must reflect the order in which the various sides of the pages are to be imaged. Pursuant to generating a schedule, the print manager node passes the schedule along to various other nodes, such as a marking node and a paper handling node, to coordinate operation of the printing system during the imaging process. When an inserter is used in conjunction with a print engine, the schedule generated by the print manager will, by necessity, include information regarding the times at which insertion sheets are to be fed into a stream of imaged sheets exiting the print engine. The following patents relate to the area of sheet scheduling:
U.S. Pat. No. 5,095,342, Patentees: Farrell et al., issued: Mar. 10, 1992.
U.S. Pat. No. 5,184,185, Patentees: Rasmussen et al., issued: Feb. 2, 1993.
U.S. Pat. No. 5,337,135, Patentees: Malachowski et al., issued: Aug. 9, 1994
U.S. Pat. No. 5,095,342 discloses a printing system with an endless duplex loop in which copy sheets to be imaged are inserted consecutively into the duplex loop without placing any skipped pitches therebetween regardless of set or job boundaries. Duplex side ones from subsequent sets or jobs are used to fill any gaps which exist in the duplex side one sheet stream of earlier sets or jobs.
U.S. Pat. No. 5,184,185 discloses a printing system wherein gaps, which naturally exist in the output of printed copy sheets from a duplex paper path due to duplex printing, are selectively combined with interset interval skipped pitches so as to provide an appropriate interset interval between each set of printed copy sheets output from a printer, while minimizing the number of skipped pitches which actually need to be scheduled.
U.S. Pat. No. 5,337, 135 discloses a trayless duplex printer with a variable path velocity. The printer includes a paper path loop with plural drives driven by a variable speed drive. Through use of the variable speed drive, interleaving spaces can be generated between duplexing path sheets. Conversely, the variable speed drive can be operated so as to close up interleaving spaces.
All references cited in the present specification and their references are incorporated herein by reference where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.